Automatic telephone system



J; l. BELLAMY' ET AL AUTOMATIC TELEPHONE SYSTEM Sept. 11, 1928;

Original F'iledfluz- 2 1925 5 Sheets-Sheet 1 UIIIII v vvvv Inusn 51:5 JuZm [Bellamy-John EEazdz-zaz HIT.

Sept. 11, 1928.. 1,683,857

J. I. BELLAMY ETA'L AUTOMATIC TELEPHONE SYSTEM Original Filed ug- 25, 1925 s Shaets-Sheet 2 JUZ'LH lBsllamBr-Juhn EEazq'nsr Sept, 11, 192s.

J. I. BELLA MY ET AL AUTOMATIC TE EPHONE SYSTEM Original Filed 1923 5 Sheets-Sheet 5 Juhn E'Earurir Jul-m IBEZZ 1,683,857 J. I. BELLAMY ET'AL AuToufATIc TELEPHONE SYSTEM ori inal Filed Aug- 25, 1925 s Sheets-Sheet 4 Sept. 11, 1928.

-Jmfi JJZm lEEZZam, 17731127 EEarc/ner 1 v vs Sept. 11, 1928.

v J. I. BELLAMY ET AL w'r on'nc TELEPHONE SYSTEM.

Oxfiginal Filed Aug. 25, 1923 5 smu -sheet 5 Inusmurs Juhn lfisllsmgtfuhn EEardnEr Patented Sept. 11, 1 928.

JOHN I. BELLAMY,

ASSIGNORS, BY

ILLINOIS, A CORPORA Application filed August 25, 1923, 'Seri or BnooKriELn, AND

res PATENT OFFICE.

JOHN E. GARDNER, OF oHIcAGo LLINoIs,

MESNE ASSIGNMENTS, TO AUTOMATIC ELECTRIC INC., OF CHICAGO,

TION OF DELAWARE.

AUTOMATIC TELEIHQNE SYSTEM.

The present invention relates to automatic telephone systems in general,- cerned more particularly with which-as is known in 5 ister, translate and a multi-ofiice telephone system;

numbers in but is condirectors, the art are used to regretra-nsmit telephone and the principal object, briefly stated, is the production of a new and improved director which is capable of being used in a telephone system in which the number of digits contained.

Reference will now ing application of Nelson,

, 1922, on which the present case filed July 6 may be considered an improve; prior case the directors are (.lesigiied to receive two office digits and numbers differ as to the be had to the co-pend- Serial lfo. 573,175,

out. In this then to receive a subscribers number consisting of a fixed number of digits.

vary

one office the number scribers number must for the reason that The number of digits may between the different oi'fices, but for any of digits in the subif a number is assignec which contains a smaller number of digits than the other numbers, switch through and the director does not free itself when the number is completed but waits for one or more other digits to be dialled, there being no means provided to cause the director to switch through when the sending mechanism catches up with the It is. accordingly, one ob registering mechanism. ect of the present invention to provide new and improved arrangements whereby -a director switches through as soon as it sends out all the digits in the subscribers number which have been stored up.

It is a.

i th plished without pulses being mutilated orlost inc 5 not yet finished scriber ha ing Sn and star the number the director Another object.- of ;the provision of arrangements for tial on the test after the director has the various switches restored to normal p Still another ob ec orovidc novel circuit e switching through any possibility of ELHY'DD- newand maintaining the test potenconductor of the director further object of the invention to arrangements whereby operation is accomase thecalldialling ts to dial about the time starts to switch through.

the present invention is improved circuit been freed, and until in the director have been osition.

t is to produce a director always be the same al No. 659,304. Renewed June 20, 1927.

in which the circuits are greatly simplified in order to render the operation more positive and less susceptible to error.

There are various other objects, having to do mainly with the various circuit details connected with'the carrying out of the main ObJGCtS of the invention, whichwill not be mentioned here but will appear fully hereinafter as the specification In addition to the co-pendin'g application of Nelson referred to hereinbefore, this application may be considered as an improvement on or amodification of the following prior, pending U. S. applications: Nelson et 211., S. N. 538,551, filed Feb. 23, 1922; Rich ardson et al., S.'N. 547,866, filed March 29, 1922; Gillings, S. N. 598,239, filed Nov. 1, 1922. 1 Referring now to the accompanying drawings,"'comprising Figs. 1-5, inclusive, they show a sufiicient amount of apparatus in a:

system embodying the principles of the invention to enable the invention to be thoroughly understood and its utility appreciated. None of the automatic numerica is further perused.

ated with it a first selector, as is indicated on the drawing, and also a' secondary switch SS, which latter has access to a number of directors, of which the one shown in Figs. 25. inclusive, is one.

The portion of the director shown in Fig. 2 comprises the sequence switch S, whose chief function is to switch the control lead from one to the other of the various operating magnets of the director. This drawing shows, also, the sequence switch S, whose chief function is to ground, one after the other, the various stop conductors associated therewith.

The portion of the director shown in Fig. 3 comprises the group of relays shown, and the associated sending switch SEN. The function of the sending switch is to count off the impulses as they are being sent out to operate the autoniatic switches, and to term1- nate the im pulses of each digit when enough have been produced.

The portion of the director shown in Fig. 41. comprises the oliice register OR, and the intermediate distributing frame IDF. The function of the otlice register OR is to record the two otlice digits of the desirednumber in preparation for their being translated into the correct digits and the correct number of digits to trunk the call to the desired ofiice.

The remaining portion of the director shown in Fig. 5 comprises the four digitregisters DR DR", inclusive, whose function to register the dig ts of the subscribelfs number asthey are received, and also to control the switching through of the director when the sending mechanism catches up with the registering mechanism.

The substatioi'i A, Fig. 1, has the usual and well known pieces of apparatus, including the calling device CD, which is used to control the register switches of the director, and also to control the auton'iatic switches in case the director catches up and switches through before the subscriber has finished dialling his number. i

The line switch C in which the line of substation A terminates. is mechanically of the well known rotary type in which the wipers have no normal position and move in a forward direction only. The secondary switch S5 associated with the repeater R, is mechanically identical with the line switch C.

The sequence switch S, Fig. 2, is mechanically a simple switch having two wipers 106 and 1.07, which are operated in a forward. direction only by the stepping magnet 103, and which are released and restored to normal by the release magnet 104:. The digit registers DR DR", inclusive, are of the same type of switch as the sequence switch S.

The sequence switch S is a simple switch comprising the wipers 1.10 and 111, which are driven in a forward direction only by the stepping magnet 108, and which are advanced uponthe dcenergization of stepping magnet 108 rather than upon the (mergization. The sending switch SEN, Fig. 3, is of the same type as the sequence switch S.

The otlice register OR is a vertical and rotary switch, and accordingly its bank contacts are arranged in horizontal rows or levels. This switch is operated in a vertical movement by its vertical magnet 307, and in a rotary movement by its rotary magnet 306, whileit is released by the release magnet 308.

The apparatus having been described more or less in general, the detailed description of its operation will now be given. F or this purpose, it will be assumed that the sul scriber at substation A desires to call a subscriber whose number, by way of example, will be assumed to be 987654. The first two of an exchange name, the calling device then being )rovided with letters in addition to the digits. l-lowever, since the lnvention is not particularly concerned with the method of listing the numbers 01" tion will bemade in the When the subscriber at substation A removes his receiver, a circuit is closed over line conductors 11 and line switch C. Line relay thereupon energizes and places ground on private normal conductors 13 ing the calling line busy immediately. The grounding of private normal conductor 13 also closes a circuit for switching relay 1 1 and stepping magnet 21 in series. As a furtlicr result of the energization of line relay 15, itconnects test wiper 23 to the junction of switching relay 14 and stepping magnet 21. The further operation now depends upon present case.

whether the trunk upon which the wipers of r the switch Asare standing isbusy or idle.

suming that it is busy, switching relay 14 is short circuited by the encountered on the busy test contact by test wiper 25, and the wipers'are advanced step by step in search of an idle trunk by the buzzer-like action of stepping magnet 21 which interrupts its own circuit, and which is opm'ated from ground encountered on the busy test contacts by test wiper 23. This opera tion continues until an idle trunkis reached, atwhich time switchingrelay 14 is no'longer short circuited and energizes.

In the present case, however, instead of asground potential sun'iiug that the trunk upon which the wipers are standing is busy, it will be assumed that the trunk is idle, in *hich case the connecting up of the test wiper at armature does not produce any particular result, and switching relay 1% energizes immediately in series with stepping magnet 21. Stepping magnet 21, however, does not energize at this time on account of the high resistance of.

switching relay 14.. Upon energizing, switching relay 14 disconnects test wiper 23 from the junction of its own winding and that of stepping magnet 21 at armature 17 and connects it tothe grounded private normal conductor 13, thereby making the seized trunk busy immediately and preparing a holding circuit for itself which becomes effective after thedeenergization of line relay .15. Also, relay 14: disconnects at armatures l6 and 18 line conductors 11 and 12 from the winding of line relay 15 and ground and extends them by way of wipers 22 and 24, bank contacts 25 and 27, trunk conductors 28 and 30, and

the repeating coil windings 31 and 32 to the upper and lower windings, respectively,-of hne relay 41 of the'repeater R. Line relay 41 now energizes over the calling line and with the particular 7 form of'calling device'used, no such assump- 12 for line relay 15 of the across the conductor-s56 and 58 extending to ,7

switch C through wiper mature and its resting contart.

'ductor 74,

closes at armature a circuit for release relay 4l2. Release relay d2, upon energizing, places ground on release tru'nkconductorQt) atarmature 17, thereby completingthe holding circuit for switching relay let in the'line test contact 26 and test This holding circuit, of course, is completed before theslow acting line relay 15 has had time to deenergi'z'e. As a still turther result oil the energization o't release relay 42, it closes at 211'11'1811118 at?) a circuit through armature 53 and its resting contact for switching relay Gland stepping mag net in series, andat arnmture d8 connects test wiper 08 to the junction of switching relay 01 and stepping magnet 62 through ar- The secondary switch SS now operates in the same manner as the line switch C to select an idle trunk. 7 Assuming that the trunk'on. which the wipers 67-69, inclusive,'are standing is idle, the steppingma'gnet 02 does not operate at all ,andswitching relay 61 energizes immediately; prepares a circuit- "For repeating v relay sd at armature 6 3; prepares the l11'1Pl1lS- ingcircuit at armature 66; and at armature 64; places a shunt around armature 5% and its working contact, thereby completing a bridge the associated first selector. 'lhisbridge includes the right hand repeating-coil windings and 3 1 and armature '55 and its resting contact. As a t'u'rtherresult of the energizationot switching relay 01, it disconhects test wiper 68 from the junction or switching relay 61 and stepping magnet 62 and connects it to ground, thereby making the seized director busy.

lnthe director switch release relay 203 now energizes over the following circuit: from ground by way of the working contact oi armature 65 of relay 61 of the secondary switch SS, Fig. 1, and said, armature, test wiper 68, test contact 71, release trunk con- I normally closed contacts controlled by armature 207, and relay 203 to battery. Relay 2023, upon energizing, opens the various restoring circuits ot'the director at armatures 209-212, inclusive, and at arma ture 210 places ground 'on the bank of the sending switch SEN preparator uent operation of the said seuding switch.

The above operations have all taken place in response to the removal of thereceiver at the sub-station A; andthe circuits are now in readiness itor the first ol'lice digit 9e; be transmitted. W hen the calling device CD manipulated in accordance with he vfir'st'otlice digit 0,11 corresponding number of interrupe the oliice register OR, Fig.4,as follows from 'to the sub ground by way of the resting contact of armature 4st)" of line relay 11 and said armature, working contact of armature 66 andsaid armature, wiper G9, bank contacts 72, impulse conductor 75,.slow acting series relay 102, Fig. 2, wiper 107 of the sequence switch S, conductor 121, and vertical magnet 307 to battery. By the operation of vertical magnet 307', the wipers 311-31e1, inclusive, of the ollice register 011, are raised step by step and come to rest opposite the ninth level of bank contacts. Relay 102 is energized in series with vertical magnet- 2-507 upon the first impulse of current deliver-ed to the latter, and being slow acting retains its armature 11 1 attracted throughout the entire series of impulses. Upon energizing, relay 102 closes a circuit for the associated slow acting relay 101, and relay 101, upon energizing, prepares a circuit for stepping magnet- 103 of the sequence switch S at armature 115.

"At the end of the series of impulses delii ei'ed to vertical magnet 307 of the office Oil. series relay 102 deenergizes and s at armature 11 1 the circuit oit step- 3 1 103 of the sequence switch S, :1! 0 opening the circuit of slow acting relay 101.

his calling device CD in according with the second ol'lice digit 8 of the desired number, line relay 41 of the repeater R dcenergizes eight times momentarily,and upon each de energization sends an impulse of current over the previously traced circuit to wiper 107 ot the sequence switch S and thence by way of conductor 122 to rotary magnet 306 ot' the ofiice'regster OR. l.\ccordingly, rotary magnet 306 receives eight-impulses 01? current and I steps. the wipers 5311-31 1. inclusive, into engagement with the eigl'ith set of bank contacts 321%21, inclusive, in the ninth level. The sequence switch S is advanced one step atthe end of this digit in the previously described manner, and -wiper 106 places ground on start conductor 1114:, thereby starting the sending equipment into operation. Before the operation of the sending equipment is taken up, the description of the registration of the remainin digits in the desired number will be completed.

The wiper 10? is now in engagement with its third bank contact, and, accordingly, when the calling subscriber manipulates his call ing device in accordance with the first digit '7 in the number of the desired subscriber, seven impulses 01 current are delivered over the previously traced circuit to wiper 107. and thence by way of the third associated bank subscriber manipulates,

Stepping magnet 10301? the sequence .the fifth impulse four bank contacts.

bank contacts 321 ment withthe bank contact in which the seventh impulse stop conductor- 2 17 terminates.

The wipers of ,the sequence switch S are again advanced one step upon the termination of this digit,and when the second digit 6 is called, stepping magnet of the second digit-register DR is operated over conductor 132an d steps the wiper .406 into engagement withthebank contact in which thesixth impulse stop conductor24e6terminates.

vSimilarly, the sequence switch S is again advanced one step at the end of the second digitfi, and when the thirddigit in the desired number is called, step ping magnet 4-03 of the third digit register DH is operated over conductor 133 and steps wiper e107 into engagement with the bank contact in which stop conductor 245 terminates. I

The wipers of the sequence switch S are again advanced upon the termination of the third digit 5, and, accordingly, when the fourth and last digit 4 in the number of the desired subscriberis. called, stepping magnet of the fourth digit register DR receives four impulses of current over the operating circuit and through conductor 13%, andsteps the wiper 41-08 into engagement with the bank contact in which the fourth impulse stop eonductor 294 terminates.

At the end of the transmissionof the last named series of impulses, the wipers 106 and 1070f the sequence switch S are advanced into engagement with the seventh set of bank contacts, and wiper 107 engages a dead contact.

The operation of the sending equipment will now betaken up. It will be noted that the oliice register OR has .four wipers, and that the set of bank contacts shown comprises This permits a maximum of fourseries of impulses to be sentout to effect the trunking of the call to the desired oilice. In order to trunk the present call through to ,the desired office, it is assumed that it -is necessary to transmit only two series of impulses, the'first comprising three pulses. Accordingly, the first and second and 322 of the n nety-eighth .EiOChSESOClfliZGd with the oflice reg ster OR are connected by means of the IDF jumpers 301 and 302 to the skip conductor 305, and the third bank contact 323 is connected-by means of the jumper 303 to the thirdimpulse .stop conductor 243, while the fourth bank contact- 204 is connected by means ofthe ,jumper304 to'the ninth impulse stopconductor24r9.

It will be remembered thatwiper 1 06 of the sequenceswitch S, upon being advanced into engagement with the third associated ,bank

the sequence switch I S.

contact at the termination of thesetting of the oflice reg'ster OR, places ground "on start conductor 114:. Accordingly,sjendi1ig relay 204;, Fig. v3, commeneesto energi z eand deenergize under thecontrol of interrupter. 226. The ground ivotential, which is placed onstart conductor 1 14, 'als o ezrtendsby way of wiper 111 of the sequence switchS, the first associated bank contact, conductor 1 11, the

first wiper 3l1 of the otiice register OR, bank .7

contact-321, jumper 301., skip conductor 305, interrupter contacts 109 and stepping mag net 108 of the sequence switch S fto'battery. Stepping magnet 1 08, accordingly, energizes jandinterrupts'its own circuit at contacts 109, whereupon it deenergize's and advances the wipersi110 andlll into engagementwithithe secondset ofibank contacts. ,When this occurs, the ground potential isextended jby wiper 111 over conductor 1&2, the second wiper 3120f the office register OR, bank contact 322, and jumper 302 to the skip conductor 305. Stepping magnet 108 is accordingly energized, and againinterrupts its owneircuit at contacts 109, whereupon it deenergizes andadvancesthewipers 110 and 111 in- V to engagen'ient with the third set of bankcontacts. The movementofthe sequenceswitch S is arrested at this point and the Wipers 110 and 111 remain in'their presentposition i for the time being.

Upon the first effective energization of sendingrelay 20 1 in response to the above mentioned grounding of startconductor 11 4, 's'endingrelay 203 closes'a circuit for stepping magnet 223 of the sending switch SEN at armature214 Upon energizing, magnet attracts its armature causing the pawl thereof to engage the next notch in the associated wiperdriving ratchet wheel. Then, upon the 1 following .deensrsi en Of lj'Q Y i Q ma of steppingmagnet 223 is openedand it deenergizes, advancing the wipers 22 4 and 225 in a clockwise direction into engagement with the first set of bankcontacts. Wiper 22 4 closesa circuit for pick-up relay 205, which becomes energized prepares a locking circuit for stop relay 206 at arl'nature 217 prepares the impulsing circuit V at armature 216; and at armature 215 closes a circuit, from ground througharmature218 and its resting contact for stepping magnet 108 of Stepp n magnet 10S thereupon energizes and attracts its armature, causing-the pawl thereof to engage anassociated wiper driving the r'epeater'xR as follows: from ground by ,way of workingeontact qfarmature216 iii relays 205'and 206 to fall back andsaid armature, Working contact of arn'iature 213andsaid armature, conductor 73, bank contact 7 0 wiper 67 armature 63 and its working contact, normally closed contacts controlled by armature 50, and repeating re lay M to battery. Each time the above circuit is closed, repeating relay 44L energizes and opens the bridge across conductors 56 and 58 at armature 55. v

The operation continues described until wiper 225 arrives upon the bank contact in which the third step conductor 2 2-3 terminates, at which time three impulses oLt'current have been delivered to. repeating relay 44: of the repeater iL-liig. 1.} arrives upon the fourth associated bank contact, stop relay 206 following circuit: from ground by way of the start conductor 11%, Fig. 2, wiper 1111 of the sequence switchS, the third associated bank'cont-act, conductor M3, the third wiper 313 oi the oiiice register OR, bank conta 323, juniper 808, the third impu stop conduetor 2&3, wiper 225 of the sending switch SEN, Fig. 3, and stop relay 200 to battery. Stop rel.ay2i.r thereupon ei'iergizes; closes a locking circuit for itsel'i at armature 220; disconnects sending relay 20d at armature 221 while it is still in a deenergised conditio' and at armature 218 opens the circuit of st ping magnet 108 or the sequence itch ti", whereupon stepping magnet 108v deenergizos and advances the wipers 110 and 111 into engagen'ient with the next set of bank contacts. As a still further result of the energization of stop relay. 206, it connects wiper to stepping magnet through interrupter contacts222 at armature 219. c Stepping magnet 223 potential placed on the bank contacts of wipe-r 224- at armature 21.0 and its working contact and interrupts its own circuit at armature The wipers 224tand 225 are, accord,- ingly, advanced step by step by the buzzerlike action of stepping magnet. 223 until. wiper 22st passes off the last grounded bank contact. When wiper 22st passes ed the last grounded contact, in ad (lit operation of steppingniagnet 223, 'itopens the circuit of pick-up. relay 205. Pick-up relay 205, however, is slow acting and does not "fall back immediately.

As a result oi the threeintcrruptions produced in the bridge across'conducto-rs 56 and 58,. the selector switch associated with the caused to raise its wipers op-v repeatcr R. posite the third level and selector In the eirector, pick-uprelay 205 deenergizes after an interval and opens the circuit of stop relay 206 at armature 217, and after an interval slow acting stop relay G (le energizes and connects up sending relay 204 ag in. The interval of time required for select an idle oliicc impulses have been sendth Wiper l' i hen wiper 225 is energized over the thereupon energizes from the ground ion to stopping the one after the in selecting an idle trunk.

starts to vibrate again under the control of 'nterrupter 226, and as a result a second series of impulses is sentout over the outgoing control conductor 73 to repeating relay a4 ofthe repeater R. These impulses are counted oil" in the abovemanner by the sending switch SEN, and when nine 225 of the sending switch SEN arrives upon the bank contact in which theninth impulse stop conductor terminates, thereby completing the following circuit: from ground by way of the stop conductor controlwiper ill of the sequence switch S, the fourth associated bank contact, conductor M l, the fourth wiper 31a of the olriceregister OR, bank contact 2324, IDE juniper %,,and thence by way of the ninth impulse stop conductor 2&9 to battery through wiper of the sending switch SEN and stop relay 206. The energization of stop relay 2% ternii'nates the second series or impulses being delivered to the repeating relay 44. of the repeater R, and causes the sequence switch 5 to advance its wipers into engage-- ment with the next, set of bank contacts. The sending switch SEN is also advanced automatically to its normal position.

Relay 204 now The first digit 7 in the subscribers number,;

which is stored on the lirst digit register DB Fig. 5, is next transmitted." The series of. seven 7 impulses representing this digit are terminated upon stop relay 206 being energized'c-ver conductor 151 and throughwiper 205 of the first digit register DR}, whichis standing on the bank contact associated with the seventh impulse stop conductor 247.

The sequence switch 5 is again automatis cally advanced and brings the stop conductor control wiper lll into engagement with, the second digit stop conductor 152, and as a result the second digit (3 in the desiredsubscriherb number, utter having been sent out ina manner described, is terminated upon the ar al of wiper 225 of the sending switch SEN upon the bank contact in which the sixth impulse stop conductor 2&6 terminates. The circuit oi stop reiay 206 at this time includes conductor 152, wiper 406 of the second digit register DB the seventh associated bank contact, and the sixth impulse stop conductor 2%. j,

At the end of the transmission of this series of impulses, the wipers of the sequence switch S are advanced into engagement with the next set of bank contacts n preparation for the sending out or the third d gitfi in the 'snbscribers number.

1 conductor 153,

57 and opens its initial H 112, and the upper winding of relay engagement with tlie'bank contact in which the fifth impulse stop conduct0r'245 terminates,'therebycompleting a circuit for stop relay 206 which includes the third digit stop wiper 4107 of the third digit register DR, the sixth associated bank contact-,and the iifth impulse stop conductor 245.

The nextand last digit 4- is now transmitted and is terminated on the energization of stop relay 206, which'occurs in response to wiper 225 coming into engagement with the bank contact in which the fourth impulse stop conductor 24:1 terminates; The circuit of stop relay 206, at this time, includes the fourth digitstop'conductor 154;, wiper 1-08 of'the fourth digit register DR, the fifthassociated bank contact, and the fourth impulse stop conductor 24 i. When sequence switch S vanced, as it is upon'thc above mentioned energization of stop relay 20(S, the grounded wiper 111 comes into engagement with the next bank contact, thereby placing ground on the incoming impulse conductor 75. This conductor is at this time disconnected in the director owing to the fact that wiper 107 of the sequence switch Sis standing on a dead. contact. The impulsing circuit, however,'extends in the repeater R through armature 10 of line relay 41 and its working contact, to the windingof switching relav l3 through the normally closed contacts controlled by armature 51. Relay 13 accordingly energizes; locks itself to release trunk conductor circuit at armature 51; places a shunt around ar-n'iature 6 1 and its working contact of switching relay 61 at armature 54; removes repeating relay 14 from under control. of the director and places it under the control of line relay tl at arn iature 50; opens a point in the previously closed-test circuit of the secondary switch SS at armature 52; and at armature 53 opens the circuit of switching relay 61. Switching relay 61 thereupon deenergizes and frees the director..

The connection has now been extended to the called line, and has been removed. from the control of the director and placed under the direct control of the calling subscriber;

It will be noted that the deenergization of switching relay 61 results in the ground potential being removed from release trunk conductor 74' at armature 65. Conduct-or 74, however, remainsgrounded through a circuit which has been previously closed in the director switch. This circuit is as follows: from ground by way of the off normal contacts 310 of the office register OR, conductor 7 202, Fig. 3, to release trunkconductor 74:. This ground potentialmaintains the director nonselectable to the various secondary switches, such as the secondary switch SS, until the is again advarious switches of the director have been restored to normal position as will now be switches to the connector switch which pointed out. The round' otential laced on conductor 74 through the upper winding of relay 202, in addition to maintaining the director busy, ergized. Accordingly, relay 202 energizes in series with relay203, and at armature 208, which is adjusted to come into engagement" with its working contactbefore armature 207 breaks away from its resting Contact; places ground,v through its own lower winding, on the release conductor 118, thereby closing a circuit for release magnet 1016f the sequence switch S through off normal ctmtacts 105, and similar-circuits forthc re lease magnets of the registers DR DPt", inclusive, as well as a circuit tl'irough off normal contacts 809 for release magnet 308- of the office register OR. The operation of arn'ia-ture 208 accordingly results in a locking circuit being closed for relay 202. Asa; further result of the energization of'relay 202, it disconnects relay 203 and places di rcct ground on release trunk conductor 7 1 at armature 207. In response to being dis connected by relay 202, relay 203 deener gfzes and at armatures 209 and 210 closes a restoring circuit for the sending switch SEN, which is effective in case the latter not in its normal position and which is as follows: From ground by way of the lower winding of. relay 202, resting contact of arA mature 210 and said armature, the bank of wiper 224C, wiper 224, armature 209 and its resting contact, interrupter contactsv 222 and stepping magnet 223 to battery. .As a further result of the deenergization of release relay 203, it closes'at armature 212 a" restoring circuit forthe sequence switch S",-which1 includes conductors 115, the bank of wiper 210, wiper 210, and interrupter contacts 109. All the various restoring circuits, it will be noted, include the lower winding of relay 203. Accordingly, relay .203 is maintained. energized and maintains conductor 74 grounded until the last switch has been re stored to normal position, at which time relay 203 deenergizes and renders the director accessible again.

Regarding the established connection, this connection is released in the followingmai'iner when the subscriber at substationA're places his receiver: Line relay ll deenergizes and closes a circuit through armature 50 and its resting contact for repeating relay 14, which accordin ly energizes and opens the bridge across conductors 56 and 58 at a rmature 55. Release relay 42 deenergizes after an interval and removes ground from release trunk conductor 29 at armature 4.7. Assum ing that the release trunk conductor '57 is extended through the various selector finally completed the connection to the called line, nothing further happens until the ground potential is removed from the said release;

maintains release relay 203 en ion trunk conductor in response to the deenergization ofthe release relay of thesaid connector switch, which is brought about owing to the fact that the bridge across conductors 56 and 58 is open at armature 55 of repeating relay 44. In this case, whenthe ground potential is removed from conductor 57, switching relay 14 of the line switch C and switching relay 43 of the repeater R ,deenergize immediately. Relay 43, upon deenergizing, opens a further point in the bridge across conductors 56 and 58 at armature 5 4, and at armature 50 opens the circuit of repeating relay 44, which relay accordingly deenergizes. The various selectorsincluded in the connection are released in response to the removal of ground from release trunk conductor 57.

To explain the alternative arrangement, it may be stated that ordinarily the release trunk conductor 57 is not extended beyond the originating office, and that inter-oil'lce trunks comprise only two conductors. In this case, the ground potential is removed from conductor 57 as soon as release relay 42 deenergizes, and the connection is released in the same way as pointed out above.

The operation-of the director in switching through when it catches up with the calling subscriber before he has completed dialling the desired number will now be explained. For this purpose it will be assumed that the calling subscriber is calling a number, and that he stops after calling the oHice digitsand before calling the first digit in the subscribers number. In that case, the first digit register DH is not moved from its normal position, and when wiper 111 of the sequence switch S is moved into engagement with the fourth associated bank contact upon the termination of the sending out of the last digit, ground is placed on the impulse conductor '(5 over the following circuit: From ground by way of wiper 100 of the sequence switch S, conductor114, wiper 111, the fifth associated bank contact, conductor 151, wiper 405 of the lirst digit register DB the first associated bank contact, switching conductor 227, spring 228 of the key K and its lower contact, and armature 229 and its resting contact to impulse conductor 75. The placing of ground on conductor at this time closes two circuits. One extends through series relay 102, Fig. 2, and wiper 1.07 to battery by wa of conductor 131 and stepping magnet 401 of the first digit register DB The other circuit is the previously traced one tobattery through switching relay 43 of the re peater R. Armature 51 ofswitching relay 43 is very lightly adjusted and,-accordingly,' relay 43 energizes quickly and closes a locking circuit for itself at armature 51 and then pulls all the Way up, thereby completingthe switching operation in scribed manner, leaving the repeating relay- 44 under the direct control'of line relay 41.

the hereinbefore de- 1 The connection is then completed when the subscriber finally dials the remaining digits in the number, owing to the fact that the interruptions produced in his line circuit are repeated through line relay 41 and repeating relay 44 inthe bridge across conductors 56 and 58. i

The closure of the relay 102 and stepping magnet 401 which was mentioned in the preceding paragraph .re-

sults in an incidental operation ot'the said v Magnet 401, upon, oper atmg, advances wiper 405 into engagement relay and magnet.

with the second associated bank contact.

thereby removing ground from conductor 75. y This does not affect the previously lYlQlltlOIlGCl energization of switching relay 43, however, owing-to the fact that the said relay 43 is able to close 1ts local locking circuit very much quicker thanthe magnet 401 can operate itsv comparatively heavy. armature and advance the wiper 405 out of engagement with its first contact. The energization and decnergization of series relay 102 which occurs at this time results in an illlPUlSOOfCUllQIll] being deliver-ed to magnet 103 of the sequence switch S in the usual manner. This is of no utility, however, and the various switches of the director are inin'rediately released in the hereinbefore described manner. v v

Unless special arrangements are provided to prevent it, a subscriber mlght cause one or two impulses to be lost by starting to call the next digit in the number just before or at about the same time that the director starts to switch through. Vith the present circuit through series arrangement, however, this cannot'happen,

as will now be explained. Assuming that the calling subscriber decides to'call thelnext digit in the desired number just before or at about the same time that the director starts to switch through, line relay 41, upon deenergizing, disconnects switching relay 43 at armature 46 and places ground on the impulse circuit. In-case line relay 41 falls back and disconnects relay 43 before the switching operation has proceeded far enough to re sult in armature 51 of relay 43 being brought into engagement with its associated contact, notl' ing'further happens in the repeater at this time, and stepping magnet 401 of the digit register DR is operated by the ground potential placed on the impulsing circuit by line relay 41, and steps the wiper 405 out of engagement with switching conductor 227,

and in response to each of the remaining impulses in the series the'wiper 405 is advanced anotherstep in the usual manner. is, that it relay 43 does not energize and close a locking circuit for itsel'tbetore armature 46 of relay 41 breaks away from its working contact in responseto the first deenergization ot' the line relay 41, relay 43 cannot energize until the sequence switch wiper 111 is'againadvanced, owing to the fact that before arma- The point tact andl to e'i'i'ect moved out of engagement with the associated bank contact 111 which switching conductor 22? terminates.

It will be noted that the repeated impulses are slightly held up while going to the repeater R, owi to the fact thatrepeating relay 44 is energized when line relay 4 1 isdeenergized. This is done so that a su'liicient time will elapse, after armature 46 breaks away from engagement with its workin cn- -e'tore the cireuitot relay 44 is closer the repeating of aninterruption, to bring armature 50 into engagement with its associated contact after armature 51 has been operated.

It may be pointed out that in case the director starts to switch through just before a calling'subscriber starts to operate his calling device again, theswitching through operation is effected as described hereinbefore, but the director is not yet freed and the interruptioiis are repeated ahead to relay iiand simultaneously the first digit rcgiii r DB Fig. 5, is operated over the impulsing circuit. This does not cause any harm to result, however, owing to the fact that as soon as switching relay 43 is "fully energized it opens the circuit of switching relay 61 at armature whereupon switching relay 61 deenergizes and trees the director in the hereinbetore described'manne'r.

It'w'ill be noted that'the sequence switch S, Fig. 2-, is advanced immediately following the termination of each series of impulses, and it special arrangen'ients were not made the director would cause the connection to be switched through right aw aythat is it it has caught up with the calling subscriber with the result that, it a calling subscriber should then start dialling, the series o't impulses thereby produced would be repeated ahead before the selector last operated has had time to select an idle trunk. Thisditfi: culty is taken care of, however, by maintaining conductor 22'? disconnected from the impulsing conductor 7 relay 206, Fig. 3, as long as the said stop relay 206 remains energized. This relay does not fall back, it will be remembered, until atter' a sufficient interval oi time has'elapsed tor the selector last operated. to select a trunk.

It may occasionally happen that the sending equipment of the director catches up with the registering mechanism, and that just before stop relay 206, Fig. 3, tails back to permit the switelling-through operation, the calling subscriber again manipulates his calling devicefor another digit, thereby causing the next digit register, the digit register DR for example, to be operated, which results in the switching through operation bemg delayed until the registered digit is sent out. It special arrangements were not provided, the

5 at arn'iature 229 of stop esser;

sending equipnient' might start soon a ftei" the digit register DR} has moved off normal that, in case the calling device of the calling subscriber is slightly slow, the sen dingswitch' SEN might overtake the digit register being operated be tore the latter has conipletedits operation. This, of course, would result in the premature termination of the series of impulses being sent out. In order to take care otthis situation, the relay 23l has been provided; This relay is slow actingand is maintained energized over coniiluctor 227 and through armature 229 and its working contact after the director l ias"caught up and before relay 206 ha's'tall'en back. Then, in

case the digit register DR does not/move oil starting up for an interval owing to the fact that the circuit of sending relay 20 i is maintained open at armature 232 by slow acting relay 231. By the time relay 231 falls back to start the next sending operation, the digit reg ster Bil which is being'operated, has adg' vanccd far enough to insure thatit will not be overtaken by the sending switch SEN.

It may be desirable, in certain spec fic instant-es, to provide directors which do not switch through when they catch up but wait until the complete number has been recorded and sent out. This is not necessary or even desirable in most cases, but is often desirable when the directors are used in connection with a mixed service system, such asis found when part of the ofiices'are manual and part of them automatic, such, for'eXaInp'le, as the system assumed in the co-pending applica-- tion oit' Nelson hereinbefore referred to. The chief reason, it may be pointed out, for havin a director which does not switch throng when it catches up is to permit the director to wait until the complete number has been called, and then add an extra digit in case the call is intended for a straight line manual oiiice. This extra digit is useful only in cans. ing the call indicators used in the manual oftice to switch through into display position, as is explained in the Nelson application reterred to above. Accordingly, the director shown in the present application is arranged so that it may be used either to switch through when it catches up as described hereinbetore, or may be used to switch through only after the complete number hasbeen received and sent out. Furthermore, the desired change maybe made by merely operat ing the key K, Fig. or restoring it to normal. "With the key K at normahthe director switches through when it catches up as de-. scribed hereinbefore. Vith the key K operated, however, conductor 227 is disconnected from the impulsing conductor 7 5 at spring 228, and is connected instead to stop relay 206. W'ith conductor 227 disconnected from conductor 75, the director cannot, of course,"

position.

till

switch through until wiper 111 of the, sequence switch S reaches its last bank con tact, at which time the complete number has been received and sent out. The reason for connecting conductor 227 to stop relay 206, it may be pointed out, is to prevent the ad Vance of the sending equipment ahead of the registering equipment when the director catches up. In case the director catches up,- the advance of sequence switch S, which occurs at the end of the transmission of a digit by the sending equipment, results in ground being placed upon the wiper of one of the digit registers, the digit register DB for example, while that wiper is in its normal Ground is therefore extended to conductor227, and with the key K operated, it is extended to stop relay 206. This occurs, itwill be remembered, while stop relay 206 is still energized, and accordingly stop relay 206 remains energized until the digit register DB has been moved from its normal position, and then, after an interval which is suiiiciently long to insure that the sending switch SEN does not overtake the digitregister DR", stop relay 206 falls back and again starts the sending switch. y

It might possibly be well to point out at this time that, since the repeater R is interposed in the trunk line extending to the first selector, it is not necessary to provide repeaters on the outgoing trunks. Repeaters are ordinarily provided on these trunks in order to furnish a short path for the battery feed to the calling subscriber, as well as to avoid the necessity of a third conductor in the associated inter-office trunk, and also to repeat the impulses to the associated switch in the distant office. The repeater 1% performs all. these functions, and therefore obviates the necessity of a separate repeater on each outgoing trunk. The applicants are aware that this idea is not broadly new, and that repeating mechanism has been combined with selector switches heretofore, the combination being known as a selector repeater. However, in. the present case, a considerable saving of equipment is effected, owing, to the fact that the sameline and release and repeating relays are used in the repeater R, that would be required to be duplicated in casetheoutgoing trunks were each provided with a separate repeater.

/Vhat'we claim is: v V 1.- In' a telephone system, a trunk,means for extending a calling line to said trunlna call director, means iior automatically connecting said director to said trunk responsive to said extension of the calling line, means insaid director for registering the digits inthe dc sired number as they are called, meansfor translating certain of said digits into a set of code digits, sending means in said director to; retransmitting series ofimpulses over said. trunk in accordance with the code digits and the untranslated digits to extend the connec tion to the called line, means for starting sai sending means upon the registration of the last digit to be translated, and means for disconnecting the director and for restoring it to common use responsive to said sending means catching up with said registering means at any point in the sending operation.

2. In a telephone system, a trunk, means for extending a calling. line to said trunk, a call director, means for automatically con necting said director to said trunk responsive to said extension of the calling line, means in said director for registering the digits in the desired number as they are called, means for translating certain ofsaid digits into a set of code digits, sending means in said director for retransmitting series of impulses over said trunk in accordance with the codedigits and the untranslated digits to extend the connection to the called line, means for starting said sending means upon the registration of the last digit to be translated, means for disconnecting the director and for restoring it to common use responsive to said Sending means catching up-with said registering means at any point in the sending operatiomand means also responsive to said sending means catch-v ing up with said registering means for placing the further extension of the connection under the control of the calling subscriber.

3. In a telephone system, a trunln'means for extending a calling line to said trunk, a call director, means for automatically connecting said director to said trunk responsive to said extension of the calling line, means in said director forregistering the digits in the desired number as they are called, means for translating certain of said digits into a, set-of code digits,

for retransmitting series of impulses oversaid trunk in accordance with the code digits and .the untranslated digits to extend the connecfor starting said tion to the called line, means sending means upon .the'registration of the last digit to'be translated, means for disconnecting the director and for restoring it to common use responsive to said sendingmeans catching up with said registering means, means also responsive to said sending means catching up with said registering means for placing the further extension of the connection under the'control of thecalling Subscriber, and means to prevent the loss of any part ofia digit in case the calling subscriber starts to call the next digit when the director is aboutto be disconnected. v

:4. In a telephone system, a trunk, a call director, means responsive to-a call oversaid trunk for connecting said director therewith, a plurality of registers in said director, means for operating said registers in succession for regi sterin g the digits in a called number, sending means controllable by any one of said regfor placing the sending means sending means in said director at I ; trolled over the calling line and over uniiler the control of said registers in succes= sion, and means for disconnecting said director from said trunk responsive to the placing of the sending means under the control of any unoperated one of said registers.

5. In a telephone system, a trunk line, means for connecting a calling line with said trunk line, a director, non-numerical switching mechanism responsive to the call for connecting the trunk line and said director, registers in said director responsive to impulses received over the calling line, sending mechanism in said director controlled by said registers, a train of switches for extending said i trunk line to a called line, a repeating relay in said trunk line initially controlled by said sending mechanism to operate a part of said train of switches, and means for placing said relay under the control of the calling line to operate the remainder of said switches.

6'. In a telephone system, a trunk line, means for connecting a calling line with said trunk line, a director associated with said trunk line, registers in said director consaid trun'k line, a sender in the director controlled by said registers, a repeating relay in the trunk line controlled by said sender, and means for cutting out the director and for placing said repeating relay under the control of the calling line.

7. In a telephone system, a. repeater including a line relay and a repeating relay, a director, registers in said director controlled by said line relay, a sender in said director controlled by said registers, a circuit over which the sender controls said repeating relay, and another circuit over which the line relay controls' said repeating relay. 7

8. In a. director, a series of registers each having a normal position, a sending switch, a stepping relay for said switch, a pulse circuit for said relay, a stop relay controlling,

said pulse circuit, said step relay controlled over circuits including a bank of said sender and the banks of said registers, and another circuit for said step relay including the normal position contacts in the banks of said registers but excluding the bank of said sender.

9. In a director, a series of registers, a sending switch, a stepping relayfor said sender, pulse circuit for said relay, a stop r'e'la'y energized under the control of an operaited register to open said pulse circuit, means for transferring the control of said step relay to a second register, and a circuit controlled by the second register 1n its normal position for holding said step relay energized.

10. In a director a series of registers, asending switch, a stepping relay for said sender, a pulse circuit for said relay, a stop relay energized under the control of an oper 11. In a telephone system, a group of,

trunk lines, a director, individual switches associated with said trunk lines all having access to said director, means for causing the switch associated with a trunk line which has been taken for use to connect with said director and make the same lousyto other switches, means for releasing the operated switch to free the director, means for restor ing any operated apparatus in the director to normal, auxiliary busying means the director for rendering it busy to said other switches prior to the initiation of the release of the operated switch, and means responsive to the completerestoration of the director for rendering said auxiliary means ine'rFective. I

12. In a telephone system, a group of trunk lines, directors, switching mechanism for connecting a trunk lineon which a call has been received with-an idle dircctor,means' forf husying the seized director, means for release ing the seized director and for restoring operated parts thereof to" normal after it has been used to extend the call, and means in the said director for maintaining: the busy con d-ition continuously from the time before its release is initiated until its restoration to normal is completed.

13. In a telephone system,- a switching ap pa'ratus having a test conductor, means for seizing said apparatus and forcompleting a guarding connection to said test conductor, means in said apparatus operative subsequent to said seizure to complete a second guarding connection to, said test conductor, a relay winding included in said second connection and shunted by said first connection, means for releasing said apparatus after it has been operated and for energizing said-relay windin by opening said first connection, a second relay winding energized responsive to the energizaton of the first said winding, means for subsequently opening the second said con nection, and contacts controlled by said second winding closed prior to the opening of said second connection for establishing a third guarding connection to saidtest conductor and for maintaining it until said apparatus is restoredto normal; f

14, In a telephone system, a switching apparatus having a test conductor, means for seizing said apparatus and for completing a guarding connection to said test conductor, meansin said apparatus operative subsequent restoration to normal of said apparatus for opening said third guarding connection.

15. In a telephone system, a switching apparatus having a test conductor, means for seizing said apparatus and for completing a guarding connection to said test conductor, a guard relay in said apparatus having two windings, means in said apparatus for completing a second guarding connection to said test conductor through one winding of said guard relay, said one winding being shunted by the firstsaid connection, means for releasing said apparatus after it has been operated and for energizing said relay through said one winding by opening the first said connection, a restoring circuit for said apparatus, and contacts on said guard relay operated'upon the energization thereof to'complete the said restoring circuit and to establish a third guarding connection to said test conductor, said restoring circuit including the second winding of said guard relay, whereby said guard relay remains operated after said second connection is opened to maintain the third guarding connection intact until the restoring circuit is opened. I

16. The combination, with a device for automatic telephone systems, of a test conductor upon which a guarding potential is placed while said device is in use, arelease magnet for restoring said device, a relay, a circuit for energizing said relay responsive to the removal of potential from said conductor, and a self locking circuit for said relay including said magnet.

17. The combination, with a device for automatic telephone systems, of a test conductor upon which a guarding potential is placed while said device is in use, a release magnet for restoring said device, a relay di rectly connected to said conductor and energized responsive to the removal of potential from said conductor, and means controlled by said relay for placing a guarding potential on said conductor.

18. In a director, a test conductor upon which guarding potential is maintained while the director is in use, a relay energized,

over said conductor, a second relay short circuited by said guarding potential and energized in series with said first relay when the guarding potential is removed, a release magnet, a locking circuit for said second relay in cluding said release magnet, and contacts on said second relay for placing a guarding potential on said conductor.

19. In a telephone system, a register sender including registering apparatus for registering digits in telephone numbers, and including sending means for retransmittimq the registered digits, means for taking said director for use, means for freeing said director after it has functioned, timing means in said register sender for spacing apart the digits transmitted by the sending means, means responsive to the retransmission of the last registered digit for freeing said register sender after said timing means has functioned, means responsive in case another digit is received after the last registered digit has been retransmitted and before the director is freed for delaying the freeing of the register sender until the newly-registered digit has been retransmitted, and additional timing means for further delaying the starting of the sending means only in case the last registered digit has been retransmitted before the first part of the newly-registered digit has been received.

20. In a telephone system, a register sender including means for registering a plurality of digits and for retransmitting series of impulses corresponding thereto, means for taking said register sender for use, means for starting the transmission of impulses before all the digits have been registered, and means responsive to the retransmission of the last registered digit regardless of the number of digits registered for freeing said register sender.

In witness whereof, I hereunto subscribe my name this eighth day of August A. D., V

JOHN I. BELLAMY. In witness whereof, I hereunto subscribe my name this 20th day of August A. D., 1923.

JOHN E. GARDNER. 

